Atherosclerosis, a build up of plaque in the artery lumen, causes stenoses that can occlude arteries. A common therapeutic procedure is balloon angioplasty to expand the plaque and enlarge the lumen of the vessel. In about 30-50 percent of the patients the blood vessel re- narrows causing restenosis. Several drugs that appear to have an effect on the restenotic process are too toxic or expensive to be given. The overall goal of this project is to demonstrate the efficacy and safety of the EKOs ultrasound-catheter device for local delivery of such drugs into vessel walls (transmural delivery). Our device is well characterized for use in enhancing drug transport into clots, and we are seeking to expand the applications for local delivery to other tissues. The specific aims are: 1. Fabricate a prototype transmural catheter system. Optimized transducer design for transmural drug delivery. 2. Determine the effect of ultrasound on drug deposition into normal and injured artery walls. Using heparin, anti-FGF2 antibodies and PD98059 as test drugs, quantify the amount of the test molecule that has entered the artery wall using radioactive labelling and use histological methods to show the extent of drug penetration into the arterial wall media. PROPOSED COMMERCIAL APPLICATION Our product will be an ultrasound catheter device that actively delivers drug into the artery wall for the treatment of restenosis.